Fibers for consumer use, especially fibers that are incorporated into yams, carpet products and fabrics/textiles, are constantly being evaluated for improvements with respect to aesthetics and performance. These improvements may relate to appearance retention, texture and surface appearance, softness and floorwear performance. Fibers and fiber products are also being evaluated to determine if there are more efficient and cost-effective manufacturing processes and equipment.
Fibers, which can be used in the production of carpet products, such as wall-to-wall carpet, rugs and mats, are modified and in some instances improved to provide a certain yam texture when they are incorporated into a carpet product and to provide a desired “look” for the space where the carpet product is being used. Additional issues that arise in the design of carpet fiber material and carpet products are daily and long-term performance and appearance.
One method that is being used to modify the texture of fabrics is to incorporate fibers that have mixed deniers into the fabric product. Denier (or fiber denier) is a physical property of a particular fiber and can be defined as: “A direct yarn numbering measurement, it is the weight in grams of 9,000 meters of yarn. Therefore, the higher the denier, the larger the yarn. Typical nylon carpet fiber has 15-18 denier/filament.” (see www.fabrica.com: Glossary of Fabric and Rug Terms) Another method that is being used to modify fibers and the resulting carpet or textile product is to incorporate not only fibers with mixed deniers, but also mixed lusters, such as the fiber and carpet product seen in commonly-owned U.S. patent application Ser. No. 10/602,459, which is incorporated herein by reference in its entirety.
Another method of improving the aesthetics of carpet products that is related to the mixed denier method is to incorporate two fiber types—such as a low melt continuous (minority) fiber and a bulked continuous filament (BCF) host fiber. In order to create softer resultant carpets with improved tips, surface and texture, however, the concentration of the minority fiber needs to be reduced. The reduction in concentration of the low melt continuous minority fiber can be difficult because the concentration is ultimately limited by the denier of the minority fiber. In a conventional low melt/host fiber product, the low melt continuous fiber has a yarn denier of about 20-40 denier, and depending on the denier of the host fiber, the low melt fiber constituent can greatly influence the final properties of the resultant fiber and/or resultant carpet product. Traditionally, carpet yarn deniers range between 1000 and 1500.
Caprolactam and nylon compounds have each been individually polymerized with the same compounds (i.e. caprolactam/caprolactam or nylon/nylon) by anionic polymerization in a twin-screw extruder and then tested for residual monomer content and thermal/mechanical properties; however, in both processes, there were no mixed monomer anionic polymerization, the polymerization process did not result in a pre-fiber gel composition that could be processed by any means (including extrusion), there was no pre-fiber dispersion, and there is no indication that the mechanical strength or thermal strength was improved by the single monomer/twin-screw extruder mixing process. (see Antec '93 Conference Proceedings, New Orleans, 9-13 May 1993, Vol. 1, p. 470-473; and Antec '94 Conference Proceedings, San Francisco, Calif., 1-5 May 1994, Vol. 1, p. 116-22)
Therefore, it would be desirable to produce a multiphase pre-fiber and/or fiber material and/or composition that a) has sufficient viscosity and suitable m elt strength such that it can be spun into a fiber or yarn, b) can be processed by any processing method, including extrusion, c) can be incorporated into the production of a fiber, yarn, textile and/or carpet product, d) allows for reduction of the concentration of or the effect of the low melt material component without being constrained by a particular fiber denier, e) would comprise at least two dispersed constituents and exhibits at least two definitive and differentiatable melting points, and f) would produce a composition, fiber and/or product having two melting points whereby the melt temperature of the constituent having the lower melting point is maintained primarily by minimizing/preventing co-polymerization during blending and processing steps.